wreford



` June 25, 1957 F, s, WRI-:FORD

LIQUID-comm WELDING CABLE: ASSEMBLY original Filed Feb. 11, 1948 (QQ N vR. www/ E States Patent LIQUID-COULED WELDING CABLE ASSEMBLY FrederickS. Wreford, deceased, late of Detroit, Mich., by Annie A. M. Wreford,executrix, Detroit, Mich., assigner, by direct .and mesne assignments,to Gar Wood industries, Inc., Wayne, Mich., a corporation of MichiganGriginal application February 11, 1948, Serial No. 7,597, now Patent No.2,691,691, dated October 12, 1954. Divided and this application August17, 1953, Serial No. 374,548

3 Claims. (Cl. 174-15) This invention relates to electric cables and, inparticular, to welding cables.

The object of this invention is to provide a welding cable having aliexible conduit located within the interior of the cable on each sideof the insulating barrier between the conductors of opposite polarity,these conduits carrying cooling liquid and at the same time being Iofsuch construction as to permit the liquid to pass through their sidewalls While preventing the passage of wire splinters which wouldotherwise interfere with the circulation of the cooling liquid.

This application is a division of the co-pending Wreford applicationSer. No. 7,597, filed February 11, 1948, for Welding Cable Assemblywhich was issued as U. S. `Patent No. 2,691,691 on October 12, 1954.

In the drawings,

Figure 1 is a side elevation partly in central longitudinal sectionthrough a welding -cable accord-ing to one form of the presentinvention;

Figure 2 is a cross-section through the welding cable terminal headtaken along the line 2 2 in Figure 1 and showing the cooling liquidinlet :and outlet connections;

Figure 3 is a cross-section along the line 3 3 -in Figure l, showing themanner in which the conductor ends lare secured to the terminals withinthe terminal heads;

Figure 4 is a cross-section through the welding cable along the line 4 4in Figure 1, showing the arrangement, spacing and insulation of theconductor banks within the cable;

Figure 5 is a central longitudinal section through 'a modified Weldingcable having iiexible conduits for cooling liquid arranged within theinterior `of the cable on each side -of the insulating barrier betweenthe conductor banks; Y

Figure 6 is a cross-section along the line 6 6 in Figure 5, showing thecooling liquid conduits; and

Figure 7 is a side elevation of a portion of the welding cables shown inFigures l to 6 inclusive illustrating the manner in which the cable isconnected to the external cooling liquid con-duits.

Hitherto, in welding cables made of banks of iinely stranded twistedconductors, much diiculty has arisen in lproperly cooling the conductorsand also in protecting them from breakage of the strands and consequentcarrying of the strand splinters into positions where they clog thecooling action |of the cooling liquid. It has also been found diiculthitherto, to properly unite the ends of the conductor banks to theterminals `and at the same time properly provide for the circulation ofthe cooling liquid.

The present invention provides a welding cable wherein the weldingconductors are formed of banks of line wire strands and which are spacedapart from one another on Iopposite sides of an insulating barrier sothat the cooling liquid can iloW around and between the conductor banksand also from one side of the insulating barrier to the other. Thebreakage of the strands vat the terminal heads is minimized by curvingthe terminals in an outwardly-ilared direction at the locations wherethe welding conductors emerge from their points of connection to theterminals. These connections are made by forcibly pressing bridgeportions within the terminal head rmly `against the ends yof the weldingconductors While subjecting them to heat in the presence of solder,thereby also providing passageway/s for the cooling liquid past the endsof the welding conductors. A modiiication of the invention furtherprovides liexible conduits for cooling liquid arranged Within theinterior of the cable on each side of the insulating barried between theWelding conductors, these iiexible conduits having walls which arefreely traversed by the cooling liquid but which are impervious to thepenetration of splinters of the wire strands of the cable, therebypreventing clogging of the cooling system by such strands.

Referring to the drawings in detail, Figure l shows a welding cable,generally designated 10, according to one form of the invention andhaving terminal heads or cable heads, generally designated 11 and 12(Figure 7) at opposite ends thereof. The terminal heads 11 and 12 are ofsimilar construction, hen-ce a description of one will suffce for both.The terminal head 11 is c-onnected to a cooling liquid Supply line 13from which `a branch supply line 14 runs to a conventional welding gun(not shown) which is electrically connected to the cable terminal head11, a liquid return line 1S being connected between the welding gun andthe terminal head 11. The terminal head 12 at the yopposite end of thecable 10 is provided with =a cooling liquid discharge line 16 whichinterconnects the yopposite sides of the terminal head 12 so as to carryaway the cooling liquid which has been heated during its passage throughthe welding gun and the welding cable 10.

The terminal head 11 (or 12) consists of a pair of terminals 17 and 18(Figures l and 2) of approximately semi-circular cross-section andhaving flattened end portions 19 and 20 respectively providing terminalconnections 21 and '22. The latter are connected to a conventionalwelding gun (not shown) by means of a bolt or other fastener insertedthrough aligned holes 23 and 24 in the flattened portions 19 and 20.

The terminals 17 and 18 within the terminal heads 11 and 12 have smoothexternal surfaces 25 and 26 of half cylindrical shape and are alsoprovided with at inner surfaces 27 and 28 which are electricallyseparated from one `another by an insulating strip 29. The latter at itsinner end is connected as at 30 to an insulating member or barrier 31which has an elongated cross-section (Figure 4) with a relatively thincentral portion and relatively thick opposite edge portions somewhatresembling an hour-glass or dumb-bell in cross-section. The insulatingmember 31 separates the two welding current conductors or banks 32 and33 of opposite polarity throughout their lengths. The insulating strip29 is bored as at 34 for the passage `of the same bolt which passesthrough the aligned holes 23 and 24 to connect the terminal head 11 tothe welding gun.

Each of the welding current conductors 32 and 33 is formed of a verylarge number of fine strands of wire, usually of copper, which aretwisted together into cordlike members 35 (Figure 4). These in turn aretwisted together spirally to form stranded conductors 36 and 37 ofrelatively large diameter opposite the thin central portion 38 of theinsulating member 31. Certain of the strands are twisted into smallercord-like members 39 which are in turn twisted spirally together to formsmaller stranded conductors 4t) and 41 respectively located on oppositesides of their respective larger conductors 36 and 37 and likewise onopposite sides of the enlarged portions 42 of the barrier or insulatingmember 31.

The free ends 43 and 44 of the welding current coni ductors or banks 32and 33 are mounted in recesses or openings 45 and 46 (Figures 1 and 3)of approximately crescent-shaped cross-section which are bounded ontheir inner sides by curved walls 47 and 48 andare preferably cast. Thewalls 47 and 48 are originallyA at asshow-n in Figure 6, but are curvedto their shapes shown in Figure 3 when the cable bank ends 43 and 44 aresecured in the openings 45 and 46 in a manner similar to that describedand claimed in the Wreford Patent 2,504,777, issued April 18, 1950, forWelding Cable. When this is done, soft solder is placed in the pockets49 or 50 adjacent the openings 45 or 46 and the terminal 17 'or 18 isplaced in a press and heated as shown in the above Wreford Patent2,504,777. Pressure is then exerted upon the wall 47 or 48 to bend itinto the curved position shown in Figure 3.

While this is being done, the solder melts and Hows through theinterstices between theA strands of the ne wires. The pressure resultingfrom the bending of the walls 47 and 48 into their curved positions(Figure 3) forces the strands of the welding conductors 32 and 33together into compact masses. The solder is f course used in connectionwith a flux, such as rosin, which dissolves the oxide from the wires andthe pressure, exerted by any suitable plunger, sinters the wirestogether in copper-to-copper union. When the solder seeps through theopposite end of the conductor 32 or 33 adjacent the inner ends of thewalls 47 or 48, this indicates that a sufficient amount of solder hasbeen applied. The solder also subsequently prevents corrosion at theselocations. A pressure in the neighborhood of twenty tons is preferablyemployed for this purpose. Cooling liquid is preferably applied to theconductors 32 and 33 while this is being done in order to prevent themfrom heating up to their annealing temperatures.

In order to cool the terminal heads 11 and 12 and the conductors 32 and33 within the cable 10, `and also to cool the welding gun attachedthereto, the terminals 17 and 18 are provided with transversepassageways 51 and 52 (Figures l and 2) which extend in oppositedirections and are threaded as at 53 and 54 for connection to thecooling liquid lines 13, and 16 (Figure 7). The inner ends of thetransverse passageways 51 and 52 are connected to the ends oflongitudinal liquid passageways 55 and 56 leading to the pockets 49 and50 respectively. The curving of the walls 47 and 4S (Figures l and 3)results in the provision of liquid passageways 57 and 58 leading fromthe pockets 49 and 50 into the interior of the cable 1G. The insulatingstrip 34 is provided with a hole 59 (Figure l) interconnecting thepockets 49 and 50 so that cooling liquid may pass freely therebetween.

The cable 10 is encased in a tubular sheath or casing 60 ot' insulatingmaterial, such as rubber or synthetic rubber, and this is clamped to thecable terminal heads 11 or 12 in any suitable manner, such as by theclamping rings 61 (Figure l). TheV insulating member or barrier 31divides the interior of the cable 10 into two chambers 63 and 64containing the welding conductors 32 and 33 respectively. The insulatingbarrier 31 has a very loose t within the sheath 60 (Figure 4) so thatliquid may pass between the inner wall 62 of the sheath 60 andtheadjacent outer edge portions 42 of the barrier 31 `from the chamber 63to the chamber 64 and vice versa.

The inner end portions 65 and 66 of the terminals 17 and 18 (Figure l)are ared outwardly as at 67 and 68k respectively in curved surfaces,preferably of hyperbolic longitudinal section. This constructionminimizes the breakage of the strands of the conductors 32 and 33 whichordinarily occurs adjacent the terminal heads of welding cables, byeliminating sharp edges which might serve as fulcrums, and insuring thatthe portions thereof adjacent the ared surfaces 67 and 68 bend graduallyand evenly as the cable 10 itself is bent during handling.

Thek appearance of the cables 36, 37, 39 and 41 in Figure 4 is purposelyexaggerated to show the manner in which the sets of three cables eachare united to form the welding conductors 32 and 33 respectively. Inactual practice, these cables are larger in diameter and are not spacedapart from one another to the extent shown in Figure 4, but till thechambers 63 and 64 more fully than Figure 4 shows. There is stillsuicient space, however, for the cooling liquid to travel through thecable.

In the operation of the invention, assuming that a conventional weldinggun has been connected to the terminal head 11, the cooling liquidsupply line 13 (Figure 7) is connected to a source of cooling water orother cooling liquid, the current is turned on and welding operationsare conducted in the usual manner. The cooling liquid passes from theliquid supply line 13 through the passageways 51 and 55 of the terminalhead 11 into the pocket 49, thence through the passageway 57 into thechamber 63 surrounding and containing the conductor 32. At the sametime, a portion of the cooling liquid passes through the hole 59 to theopposite side of the terminal head and continues through the passageway58 into the chamber 64 surrounding and containing the conductor 33. Theliquid passes lengthwise through the chambers 63 and 64 to the oppositeend of the cable where it enters the terminal head 12. As previouslystated, the latter is of similar construction to the terminal head 11.

The ow of the electric welding current through the conductors 32 and 33heats up the individual strands of ne wire of which these are composed,and since the welding current is ordinarily 60 cycle alternatingcurrent, the fluctuation thereof causes the wire strands to move apartand together alternately in rapid succession. This action moves thecooling water in and out through the interstices between the strands,carrying away the heat and preventing damage to the cable 10. At thesame time, the heated cooling liquid returning from the welding gunthrough the conduit 15 passes through the passageways 54 and 56 into thepocket 50, thence through the passage- Way 58 into the chamber 64 withinthe cable sheath 60, and accompanies the other cooling liquid in itscourse lengthwise through the cable 10. Some of the cooling liquid owspast the edge portions 42 of the-insulating member or barrier 31 betweenthe chambers 63 and 64. The heated cooling liquid passes outward throughthe passageways 55, 56 to the terminal head 12 into the cooling liquiddischarge line 16. The cooling liquid ordinarily employed is ordinarytap water which, on account of its low electrical conductivity, preventsshort-circuiting of the welding conductors, which are carrying thewelding current of low voltage but high amperage.

The modification shown in Figures 5 and 6 is generally similar inconstruction and operation to the principal form of the invention shownin Figures l to 4 inclusive and is similarly connected as in Figure 7.Similar parts of FiguresS and 6 are therefore similarly designated tothe corresponding parts in Figures 1 to 4 inclusive. Positive cooling ofthe conductors 32 and 33 in Figures 5 and 6, however, is insured bymeans of flexible conduits 70 and 71 respectively arranged within theinterior of the cable on each side of the insulating barrier between theconductors 32 and 33, the conductors being wound around their respectiveconduits during manufacture. The exible conduits 70 and 71 arepreferably formed of spirally wound stock, so that their side walls arepermeable to liquid which can push its Way out through the spiralinter,- stices between the spirally wound wires 72 and 73 making up theside walls of the conduits 70v and 71. At the same time, however, theseinterstices are so narrow in width that they effectively` bar the entryof any splinters Vof wire strands which may be broken off from the`individual Wires of which the conductors 32 and 33 are made up. In thismanner, the splinters are prevented from clogging the cooling lines, andthe exibility of the conduits 70 and 71 enables the cable 10 to be bentfreely without interfering with the tlow of the cooling liquid.

In actual practice, the cables 36, 37, 39 and 41 will not be of circularcross-section as shown in Figure 4, after they have been assembled.After assembly, these cables will flatten out and their strands willalmost completely ll the space within the cable sheath 6d. The strands,however, leave suiiicient spaces for the passage of the cooling waterbetween them.

In actual practice, also, the entire internal assembly is twistedbodily, including the insulating member or barrier 3l. This is done in amachine which twists the internal assembly while assembling theconductors alongside the insulating member 31. The twisting may takeplace at any desired interval, a complete turn every 9 inches beingfound satisfactory. This twisting imparts llexibility to the cable whichit would not otherwise easily possess, due to the resistance of theinsulating member 31 to twisting in the direction of its edges. Thecable 19 of the present invention is also especially well adapted to theuse of a binder strap dla (Figure in place of the clarnping rings 6l,because the surfaces 25 and 25 are on relatively thick and strongportions of the terminals where they serve as anvils for sustainingheavy pressure. For this reason, the clamping rings 61 or bands 61a maybe clamped more tightly than in prior welding cables because such priorcables were structurally weak at the locations where the clamping ringswere attached. Certain of these prior cables, for example, attached thecable sheaths to a short section of structurally weak brass tubing. Thepresent construction enables a stronger connection to be made and alsoprevents leakage of the cooling water at such connections.

What I claim is:

1. A ilexible cable unit for welding equipment comprising a tubularinsulating casing, a plurality of iexible welding current conductorswithin said casing, a transversely-extending insulating barrier arrangedlengthwise between said conductors, and terminal heads connected to theopposite ends of said conductors, at least one of said terminal headshaving a pair of elongated terminals therein arranged side by side inlaterally-spaced relationship and having approximately semi-cylindricalrearward portions disposed within said casing, and an elongatedlongitudinal insulating element disposed in the space between saidterminals, said rearward portions of said terminals having recessesextending longitudinally inward from their rearward ends, said conductorends being secured to said terminals within said recesses, and saidrecesses having inner walls extending transversely across said terminalsadjacent the space therebetween, said inner Walls being disposed inclamping engagement with said conductor ends, said terminals havingcooling liquid passageways therethrough leading from the exteriorthereof into said recesses, and exible cooling liquid conduits withliquid-permeable walls disposed within the interior ot the cable on eachside of the insulating barrier between said conductors in communicationwith said recesses and extending lengthwise of said cable unit.

2. A flexible cable unit for welding equipment comprising a tubularinsulating casing, a plurality of tlexible welding current conductorswithin said casing, a transversely-extending insulating barrier arrangedlengthwise between said conductors, and terminal heads connected to theopposite ends of said conductors, at least one of said terminal headshaving a pair of elongated terminals therein arranged side by side inlaterally-spaced relationship and having approximately semi-cylindricalrearward portions disposed within said casing, and an elongatedlongitudinal insulating element disposed in the space between saidterminals, said rearward portions of said terminals having recessesextending longitudinally inward from their rearward ends, said conductorends being secured to said terminals within said recesses, and saidrecesses having inner walls extending transversely across said terminalsadjacent the space therebetween, said inner walls being disposed inclamping engagement with said conductor ends, said terminals havingcooling liquid passageways therethrough leading from the exteriorthereof into said recesses, and flexible cooling liquid conduitsdisposed within the interior of the cable on each side of the insulatingbarrier between said conductors in eommunication with said recesses andextending lengthwise of said cable unit, said conduits having perforatewalls for the passage of cooling liquid therethrough whereby to excludebroken wire splinters from the interior of said conduits.

3. A flexible cable unit for welding equipment comprising a tubularinsulating casing, a plurality of flexible welding current conductorswithin said casing, a transversely-extending insulating barrier arrangedlengthwise between said conductors, and terminal heads connected to theopposite ends of said conductors, at least one of said terminal headshaving a pair of elongated terminals therein arranged side by side inlaterally-spaced relationship and having approximately semi-cylindricalrearward portions disposed within said casing, and an elongatedlongitudinal insulating element disposed in the space between saidterminals, said rearward portions of said terminals having recessesextending longitudinally inward from their rearward ends, said conductorends being secured to said terminals Within said recesses, and saidrecesses having inner walls extending transversely across said terminalsadjacent the space therebetween, said inner walls being disposed inclamping engagement with said conductor ends, said terminals havingcooling liquid passageways therethrough leading from the exteriorthereof into said recesses, and flexible cooling liquid conduitsdisposed within the interior of the cable `on each side of theinsulating barrier between said conductors in communication with saidrecesses and extending lengthwise of said cable unit, said conduitscomprising spirally-coiled members providing interstices therebetweenfor the passage of cooling liquid whereby to exclude broken wiresplinters from the interior of said conduits.

References Cited in the le of this patent UNITED STATES PATENTS2,222,574 Robertson Nov. 19, 1940 2,282,003 Scott et al. May 5, 19422,320,470 Rees s June 1, 1943 FOREIGN PATENTS 553,145 Great Britain May10, 1943 OTHER REFERENCES Uniflex Welding Cables, Uniflex Catalog U, 4pages. Copy received in Patent Ollice May 7, 1948. Copy in 174-15.

